High-resolution, nonmechanical approach to polarization-dependent transmission measurements

We have implemented an automated, nonmechanical approach to the measurement of polarization dependent loss (and, equivalently, gain). We use a deterministic fixed-states method to derive Mueller matrix elements from intensity measurements at specific polarization states. Voltage-modulated liquid-crystal variable retarders set the polarization states. Synchronous detection is employed to increase the signal-to-noise ratio (SNR) of the system and thereby allow measurement resolution to better than 0.001 dB. We present polarization-dependent loss measurements from 0.0016 to 0.56 dB at 1550 nm to verify performance.